Generally, there are different kinds of products that contain contents such as liquid. The most general product is completed by sealing a bottle with a bottle cap after containing contents in the bottle. The bottle is of glass, plastic and metal.
Such a bottle product includes a bottle and a bottle cap. There are different kinds of bottle caps. That is, there is a simple bottle cap that can be opened using an opener. There is another bottle cap that can be opened by turning the cap through a screw. In this case, the screw is formed on an outer surface of a bottle nozzle and is engaged with a screw formed in the bottle.
The products based on the above bottle caps do not have any special problems in case that they contain cheap contents. However, in case that they contain expensive contents, problems are likely to occur. That is, the expensive contents may be exchanged with the cheap contents.
To prevent such a problem, various methods for sealing a bottle cap are being contrived but there is no method for solving the problem at present.